Answer:
XY = 74
Step-by-step explanation:
Using the information given, plug it into the perimeter formula [P=2(l)+2(w)]
90 = 2 (5y - 1) + 2 (4y + 1)
Distribute
90 = 10y - 2 + 8y + 2
Combine like-terms
90 = 18y
Isolate the variable
y = 15
Then, plug it into XY
5 (15) - 1
Multiply
75 - 1
Combine
74
XY = 24
The perimeter of the rectangle is
2(5y - 1) + 2(4y + 1) = 90 ← distribute parenthesis on left side
10y - 2 + 8y + 2 = 90
18y = 90 ( divide both sides by 18 )
y = 5
XY = 5y - 1 = (5 × 5) - 1 = 25 - 1 = 24
